Petroleum product storage and distribution has been a large industry for many years. During the growth of this industry, systems have been developed for storage and distribution at service stations and fuel depots all over the world. Systems have been developed to store petroleum products in large underground storage tanks, with piping systems designed to transfer the fuel to individual pump dispensers or to other tanks for mixing or blending before final distribution.
As part of that development has been the effect that these systems have on the environment, both from a concern for prevention of leaks and spills and from a safety concern. Systems have been developed in which a primary pipe is used for supply of the gasoline or other petroleum product and a secondary or containment pipe is placed on the outside of the primary pipe to provide a secondary barrier to escaped fuel or damage to the piping system.
As the fuel distribution systems have become more complex, and efforts of containment and protection have increased, chambers or sumps have been used at various points in the system, particularly at junctions and originating or dispensing stations. As is becoming more and more common in the petroleum product industry, these sumps are usually located at the lowest point in the path of piping lines which contain petroleum products such as gasoline and the like.
The sumps are also likely to collect water from rain or run-off from washing or simply from ground water that seeps into the sump. Depending upon the particular conditions of climate and usage, the sump may contain little or no water or the sump may be nearly full of water. In prior art systems, the only way that leakage of fuel into the sump or the piping lines could be discovered was to open the sump and look or smell to detect the presence of gasoline or other hydrocarbon products.
This use of visual or olfactory senses to detect leaks has not been particularly successful for several reasons. If the leak is small, or perhaps represents a spill which is non recurring, there is no really safe and effective way to remove the fuel. Yet, the presence of small quantities of gasoline and the like represents a serious hazard as a potentially explosive condition and removal of the hazard is necessary. Moreover, such a detection system requires regular and frequent inspection, thereby requiring a significant labor cost.
There have been some attempts to install a detector system in sumps and the like but they have not been successful in detecting and removing small quantities of flammable liquids. As has been noted, most sumps collect varying quantities of water as part of normal operations of the piping systems. Any detection device which might be installed would have to distinguish between the presence of water and the presence of flammable or explosive liquids such as gasoline. Water is not only tolerated but is expected to be present in much larger volumes than would be tolerated if the liquid were explosive or flammable. Since most hydrocarbons and petroleum products are lighter than water and are also not miscible in water, the petroleum product tends to float on top of the water in the chamber. When water levels vary greatly in any given sump, placement of the detector becomes difficult if not impossible. Such a system and method would be of great advantage in the art.
Flammable liquids such as gasoline and the like are potentially quite dangerous because of the capability of these liquids to explode when mixed with oxygen in certain ratios and when confined to closed environments. Sumps which are located at low points on the piping system are often collection points for drainage of leaks or spills of fuels from remote places in the system, so that the potential for an explosion may not even be known to exist. Inspection by a human may itself be dangerous or potentially the source of a spark to cause combustion of the explosive fuel and air mixture.
Also, since sumps are expected to fill with water, often these sumps are provided with pumps which remove the collected water from time to time. Not only is it important to prevent explosions at this time, it is desirable that no contaminating petroleum products be present in the water as it is pumped from the sump and discharged, perhaps into a sewer or other waste disposal system.
Accordingly, it is an object of the present invention to provide a system and method for neutralizing flammable liquid contamination of petroleum product storage and distribution systems.
Another object of this invention is to provide a device and method for neutralizing flammable liquid contamination in the presence of water, no matter how much or little water is present at the time of the contamination.
Yet another object of the present invention is to provide a device capable of operating to neutralize flammable liquids automatically and without need for human supervision.
Other objects will appear hereinafter.